[llvm] [DemandedBits] Support non-constant shift amounts (PR #148880)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> > > my transformation contains a loop and the Alive syntax doesn't permit loops
> > 
> > 
> > You can use a smaller integer bitwidth (e.g., i4/i8), then unroll the loop with `-src-unroll=8 -tgt-unroll=8`.
> 
> Thanks for the tip. Here is the updated proof --> https://alive2.llvm.org/ce/z/tCvUT6

In your proof, the range of shamt is not taken into account. Updated: https://alive2.llvm.org/ce/z/n4hgkX
Can you please add proofs for shl nsw/shl nuw/lshr/lshr exact/ashr/ashr exact?
Then you should paste the links into the PR description.


https://github.com/llvm/llvm-project/pull/148880